USER’S RESOURCES BOOK WEIGHING ACADEMY Weighing History Version 1.01 September 2004 Kadlec, spol. s r.o. Veleslavínova 19 746 01 Opava This project has been funded with the support of the European Community. The content of this project does not necessarily reflect the position of the European Community or the National Agency, nor does it involve any responsibility on their part. (c) 2004 All rights reserved Weighing Academy Weighing History Content Content........................................................................................................................... 2 1 History of the measurement and comparing of the weight from Antique till today.......... 3 1.1 Origin of the need of measurement and comparing of the weight............................ 3 1.2 Types of scales in a history .................................................................................. 3 1.3 Weight unit......................................................................................................... 5 1.4 Mass units .......................................................................................................... 5 1.4.1 Old mass units ................................................................................... 5 1.4.2 Contemporary mass units ................................................................... 6 1.5 Conversion tabs of weight quantity....................................................................... 8 1.6 Other types of scales in history: ..........................................................................11 1.7 Preciseness of mechanical scales:........................................................................14 1.7.1 Different types of mechanical scales in history: ...................................14 1.8 Electronic scales:................................................................................................18 1.8.1 Preciseness of electronic scales: .........................................................18 1.9 Progression trends: ............................................................................................19 1.9.1 Test..................................................................................................21 page 2 / 21 Weighing Academy Weighing History 1 History of the measurement and comparing of the weight from Antique till today 1.1 Origin of the need of measurement and comparing of the weight Weighing or comparing the weigh is relayed to the humankind from its very beginning. Already a primaeval man when dividing the food speculated whether he got the bigger and heavier piece of meat than his fellow. And then first quarrels which were solved by the foundation of the weighing method had already begun. Picture of people preparing the mammoth When the time went by, in times when the exchange business started to develop, the need of weighing was sharply developing and the man came to the conclusion that if he does not weigh his products objectively, he will pray on himself. However, one reason for the introduction of the precise weighing was the collection of different fees, tariffs and taxes in a form of precious metals or in natural form so that he could control how much was money was delivered. In the ancient time the precise weighing was very important, which is proved by paintings on walls of pharaohs crypts and some preserves scales and weight units. 1.2 Types of scales in a history The very first type of scale was the isosceles scale, with the hanging product on its one side and with the weight unit on its other side to reach the balance. According to the summary of each weight unit, the total weight of the product was determined. This first type of scale was invented more than 3000 years ago and it can still be seen in different modifications in different independent cultures, which is proved by the discovered scales from different place in the world. page 3 / 21 Weighing Academy Weighing History Wall painting in the pyramid Roma isosceles scale Two kinds of old Roman scales Peruvian isosceles scales Scale for coins Persian scale with the weight unit in a wooden case Persian isosceles scale page 4 / 21 Weighing Academy Weighing History 1.3 Weight unit Weight units are as old as sales. There was used the lead tin, copper, bronze for weighing in the Antiquity. Sometimes the weight unit was made from big hew-roughly stones. Weight unit used to be made in sets of several pieces. Persian weight unit Set of weight unit 2000 years old Definition of weight unit - Technical educational dictionary 1939 “Weight units in a weighing or scaling meaning are metal bodies of specific shapes that have the certain number of weighing units (gravimetric units). They are used either to weigh unknown weight of some product or to weigh demanded amount on scales (Weight units and adjusting all scales). Weight units are the basic tools for the manufacturing of all types of scales. 1.4 Mass units 1.4.1 Old mass units We know many different kinds of mass units in which scales and weight units were calibrated. In the old Czech Bible “Kralická” we can find the mention about mass units as follows: Firstly only gold and silver used to be weighed, other materials used to be measured. There were no coins, just grains, sticks or pieces of metals in various shapes. The base of the scale (mass unit) was ąekel (sikl), in our bible lot, called lot of sanctuary. It was kept in a stall as normal. 60 lots were one mina/pound. 60 pound were centner or hrivna (talentum). In gold a lot has16g, later on it had approximately 11g. Gradually it was counted only 50 lots per libra. In silver the weight was a little lower: lot had 14g, pound had 700g and center had 42g. In the bible there are listed following scales: (with approximate conversion) 1 gera = 0.8g 20 ger = 1 lot = 16g 60 lots = 1 pound = 960g 60 pound or mins = 1 hrivna or centner (talent) = 58 kg. From preserved sources we know for example these ancient mass units: • 1 roman pound (as) = 12 uncia = 345 grams page 5 / 21 Weighing Academy Weighing History • 1 uncia = 6 sextula = 8 denarius = 24 scrupulus = 28,75 grams • 1 scrupulus = 2 obolus = 6 siliqua = 1,20 grams With the development of the business there was a big chaos in using different kinds of mass units. In Europe /except England/ there were made some experiments for unification of mass units. These efforts were not successful and definite unification began with the introduction of Parisian metric convention from 1875 that was accepted by European countries besides Anglo-Saxon countries where remained weighing in other units for a long time. Before a year 1875 so called Vienna mass units were used in the majority of continental Europe. • 1 karat = 0,000 206 kg • 1 denar = 0,001 096 kg • 1 kventlik = 0,004 375 kg • 1 lot = 0,017 501 kg • 1 mark (hrivna) = 0,280 668 kg • 1 pharmaceutical pound = 0,420 045 kg • 1 customs pound = 0,5 kg • 1 pound = 0,560 06 kg • 1 customs cent = 50 kg (10 customs pound) • 1 cent = 56,006 kg (10 pound) Examples of other used mass units: /weighing precious metals and precious stones/ • 1 Vienna hrivna of silver = 16 lots á 4 kventliks • 1 Vienna hrivna of gold = 24 karats á 12 grans (grains) English mass units: /For pharmaceutical scales – Apothecaries weight/ • 20 grains = 1 sruple • sruple = 1 drachm = 60 grains • 8 drachm = 1 ounze = 480 grains /For business scales – Avoridupois weight/ • 16 ounce = 1 pound (pound) = 7000 grains Note: In some countries pound is still used as the mass unit (1 pound = 0,453 kg) 1.4.2 Contemporary mass units Nowadays the basic unit of the SI system is 1 kilo (kg). Acceptable derived unites are: microgram (µg), milligram (mg), ton (t). page 6 / 21 Weighing Academy Weighing History The metric convention was signed by representatives from 17 countries on May 20th 1875. Then, an International office for weights and measure was built on its basis in Sévres close to Paris and it was controlled by the International committee for weights and measure. Metric convention came into effect on 1st January 1876. The metric system (because the basic unit was 1 meter) set up by the agreement had only two mass units in that time: meter and kilo. Originally the kilo was derived just from the meter. It was the weight of 1 dm3 of clear water at 4°C (at this temperature the water has the highest density). Gradually this derivation was left and there was found the new mass unit, so called etalon. This etalon is the international prototype of kilo from which other national etalons are derived. Prototype of kilo Definition of kilo Kilo is equal to the weight of international prototype of kilo that is preserved in International office for weights and measure in Sévres close to Paris. There exist a lot of national/state copies in the world. The prototype of kilo was made from the alloy of platinum and iridium (rate 9:1). On the etalon there are connected other national etalons (produced with the highest preciseness of weight) that are preserved in various countries, e.g. in the Czech Republic: ECM 120-1/00-007 Weight ETALON Category according to Quantity Unit the specialization weight weight kilo Semi-finished stadium Value, range Uncertainty Approved as the 1kg + 0,165 mg 0,004 mg state etalon in CR page 7 / 21 Weighing Academy Weighing History Etalon is defined as the weigh unit of 1 kilo made from the alloy of platinum and iridium whose value of weight is determined by the connection to International prototype of kilo that is preserved in BIMP (International office of weights and measure) close to Paris. Etalon is realized as the Pt-Ir one kilo prototype, No.67. The etalon = 1 kilo equilateral cylinder from the alloy of platinum and iridium. 1.5 Conversion tabs of weight quantity (present and historical units) mark (state) abbreviation weight (kg) kilo kg 1 metric cental q 100 ton t 1000 ton is secondary mass unit if SI metric karat Kt 0,0002 metric grain 0,00005 unit used by jewellers Nuclear mass unit at 1,6605655E-27 (Nuclear mass unit is secondary mass unit of SI, so called unitary unit that is 1/12 of weight of the aluminium isotope with the protonic number Z=6 and nucleon number A=12) metric technical mass unit 9,80665 also used as hyl keel (UK) 21540,19446656 (Unit used for weight measuring of coal.